This invention relates to a capacitor-mounted circuit board, and more particularly to a printed capacitor-mounted circuit board which has a printed capacitor mounted thereon.
A conventional printed capacitor is typically manufactured in such a manner that a glass/silver paint used for formation of a first electrode made of silver is printed on a ceramic green sheet and a dielectric paste is coated on the glass/silver paint, followed by calcination of the ceramic green sheet, glass/silver paint and dielectric paste at an elevated temperature as high as about 900.degree. C., resulting in a ceramic substrate, a first electrode and a dielectric layer being formed. Then, a second electrode made of silver is formed on the dielectric layer to complete the printed capacitor. Thus, use of ceramic for the substrate requires calcination at an elevated temperature; however, this permits the dielectric layer to be increased in dielectric constant, so that the capacitor may be provided with a relatively increased capacity. Additional techniques for forming such a printed capacitor are also known in the art, which are adapted to print a capacitor on a printed substrate such as a glass/epoxy substrate or the like. The techniques are so constructed that a conductive paste such as a resin/silver paste or the like is formed on the printed substrate to form a first electrode and then a dielectric paste is coated on the thus-formed first electrode to form a dielectric layer, on which a conductive paste is coated to form a second electrode, resulting in a printed capacitor-mounted circuit board being provided.
Formation of the printed capacitor on the ceramic substrate permits the printed capacitor to be increased in capacity, however, it causes the printed capacitor-mounted circuit board to be highly increased in manufacturing cost. In particular, large-sizing of the ceramic substrate leads to a substantial increase in manufacturing cost of the circuit board. Also, the ceramic substrate is not suitable for multilayering of the circuit board or for construction of the circuit board into a multilayered structure.
Although the printed capacitor-mounted circuit board wherein the printed capacitor is formed on the printed substrate fails to highly increase a capacity of the printed capacitor, it significantly reduces a manufacturing cost thereof and can be multi-layered.
However, formation of the conductive paste into the first electrode in the printed capacitor-mounted circuit board causes conductive powders or particles of the paste to bite into the dielectric layer, to thereby prevent the printed capacitor from being increased in capacity.